Sunlight-Mimicking LED Spectrum Using Blue and Phosphor Conversion
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Solution Overview
Problem
Indoor lighting devices exhibit a constant spectral power distribution that significantly differs from the spectral power distribution of sunlight, potentially disrupting human biorhythms and causing health issues due to excessive blue light emission, and near-UV light emitting diode chips are costly and inefficient with reliability concerns.
Innovation Solution
A light emitting device comprising blue, green, and red light emitting portions using near-UV light emitting diode chips with wavelength conversion phosphors to mimic sunlight's spectral power distribution, allowing adjustable color temperature and intensity to match natural sunlight patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If near-UV light emitting diode chips are used for wavelength conversion, then blue light can be generated, but manufacturing cost increases and reliability decreases
Solution Approach 1:
The patent extracts and eliminates the near-UV light emitting diode chip from the system by replacing it with a blue light emitting diode chip. This removal of the problematic component resolves the reliability issues and cost concerns while still achieving the desired blue light emission through a different mechanism (direct emission from blue LED combined with phosphor down-conversion).
Solution Approach 2:
The patent creates an alternative optical path that copies the desired outcome (blue light emission) without using the original problematic method. Instead of using near-UV LEDs with wavelength conversion, the invention uses blue LEDs with phosphor materials that convert some blue light to yellow-green light, creating a similar spectral output through a different physical pathway.
2Illumination intensity
If near-UV light emitting diode chips are used for wavelength conversion, then blue light can be generated, but manufacturing cost increases
Solution Approach 1:
The patent removes the expensive near-UV light emitting diode chip from the manufacturing process and replaces it with a standard blue light emitting diode chip, which is more readily available and less costly. This extraction of the problematic component directly addresses the manufacturing cost issue while preserving the blue light emission function.
Solution Approach 2:
The patent substitutes expensive, specialized near-UV LEDs with more economical blue LEDs that have established manufacturing processes and lower costs. The invention accepts the use of conventional, mass-producible blue LED components rather than relying on expensive, niche near-UV technology.
3Device complexity
If constant spectral power distribution is used in indoor lighting, then device complexity is reduced, but health issues arise due to disruption of human biorhythms
Solution Approach 1:
The patent introduces dynamic control of the lighting system by enabling adjustment of the blue light component's intensity relative to other spectral components. This allows the spectral power distribution to change over time or in response to environmental conditions, particularly to reduce blue light exposure during evening hours when it would disrupt melatonin production and sleep patterns, while maintaining simpler control during daytime.
Solution Approach 2:
The patent changes the spectral parameters of the lighting output by independently controlling the intensity of the blue light emitting portion relative to other wavelengths. This parameter adjustment capability allows optimization of the spectral composition to match natural sunlight patterns at different times of day, reducing harmful blue light exposure while maintaining overall lighting quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device provides a more uniform and continuous spectral power distribution akin to sunlight, reducing health risks and lowering manufacturing costs while enhancing efficiency and reliability.
Implementation Method 1
a first wavelength conversion portion for wavelength conversion of near-UV light emitted from the near-UV light emitting diode chip
Implementation Method 2
the first wavelength conversion portion including at least one type of phosphor to emit blue light through wavelength conversion of near-UV light emitted from the near-UV light emitting diode chip
Data Source
AI summary
A light emitting device including a blue light emitting portion configured to emit blue light, a green light emitting portion configured to emit green light, a red light emitting portion configured to emit red light, in which the blue light emitting portion include a first near-UV light emitting diode chip and a first wavelength conversion portion for wavelength conversion of near-UV light emitted from the first near-UV light emitting diode chip, blue light emitted from the blue light emitting portion includes a first peak wavelength in a wavelength band corresponding to near-UV light and a second peak wavelength in a wavelength band corresponding to blue light, and an intensity of the first peak wavelength is in a range of 0% to 20% of intensity of the second peak wavelength.